richard@berner.UUCP (Richard Greenall) (01/25/89)
I have been having a problem with the cron utility under XENIX 368 version 2.3.1. When cron is started , it will run for a while, and then apparently lock up, not running any more jobs until it is stopped, and then restarted again. This occured this morning when I scheduled a backup job with "at" to be run during the early morning. When I arrived this morning, the job had not run, and cron had not run any of its jobs since about 8 hours previous. When I killed cron and restarted it, the job was released. Does anybody know what is happening, and whether it is something I am doing or this is an actual bug in cron? thanks in advance. richard greenall watmath!dvlmarv!berner!richard uunet!mnetor!becker!berner!richard
morris@dms.UUCP (Jim Morris) (01/31/89)
From article <286@berner.UUCP>, by richard@berner.UUCP (Richard Greenall): > > I have been having a problem with the cron utility under XENIX 368 > version 2.3.1. When cron is started , it will run for a while, and > then apparently lock up, not running any more jobs until it > is stopped, and then restarted again. > > Does anybody know what is happening, and whether it is something > I am doing or this is an actual bug in cron? > Yes, I have the same problem. The cure appears to be to put a dummy entry that will make cron wake up every hour. This was suggested to me by someone at SCO. I did the following which "cured" the problem: put the following line in /usr/spool/cron/crontabs/root 10 * * * * /bin/true thats it. I don't have a clue why it fixes the problem. -- Jim Morris. morris@dms.UUCP or weitek!dms!morris Atari Games Corporation, Sycamore Drive, Milpitas CA 95035. (Arcade Video Game Manufacturer, NOT Atari Corp. ST manufacturer). Any opinions expressed are probably my own, and not those of Atari Games Corp.
croot@lynpac.oz (Admin) (02/02/89)
In article <286@berner.UUCP> richard@berner.UUCP (Richard Greenall) writes: > >I have been having a problem with the cron utility under XENIX 368 >version 2.3.1. When cron is started , it will run for a while, and >then apparently lock up, not running any more jobs until it >is stopped, and then restarted again. > > [ deleted ] > > richard greenall I have heard that XENIX/386 cron must run *something* at least once every six (or so) hours. Our /usr/spool/cron/crontabs/root file contains: 0 0,6,12,18 * * * /bin/true >/dev/null 2>&1 so force this to occur ... otherwise it dies as yours has. Matt. -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- "life? don't talk to me about life!" Matt Atterbury. :-) :-( :-) :-( "klaatu nikto barada" Lynwood Pacific, Sydney, Australia. :-( :-) :-( :-) matt@lynpac.oz.au (Europe/Internet) || uunet!munnari!lynpac.oz.au!matt (UUCP)
davidsen@steinmetz.ge.com (William E. Davidsen Jr) (02/03/89)
In article <611@dms.UUCP> morris@dms.UUCP (Jim Morris) writes: | I did the following which "cured" the problem: | put the following line in /usr/spool/cron/crontabs/root | | 10 * * * * /bin/true Ah ha! No wonder I never saw the problem. My machines as heavy uucp boxes and run uucico several time an hour to check for queued outgoing mail. No wonder I haven't seen this. Thanks for the info! -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me
richard@berner.UUCP (Richard Greenall) (02/03/89)
In article <13073@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes: >In article <611@dms.UUCP> morris@dms.UUCP (Jim Morris) writes: > >| I did the following which "cured" the problem: >| put the following line in /usr/spool/cron/crontabs/root >| >| 10 * * * * /bin/true > > Ah ha! No wonder I never saw the problem. My machines as heavy uucp >boxes and run uucico several time an hour to check for queued outgoing >mail. No wonder I haven't seen this. > I don't think that that was the entire problem with cron. I also run uucp a couple times an hour and still get the cron lockup quite regularly with 2.3.1 I even added the /bin/true to run about every half hour with little success. I even went back to the cron in version 2.2.1 and installed that, and STILL got the same symptoms. richard greenall berner!richard
aryeh@eddie.MIT.EDU (Aryeh M. Weiss) (02/03/89)
The problem appears to be the fact that the cron distributed with SCO 386 is actually the old 8086 executable where int's are 16-bits..ts. Therefore since days are 86400 seconds long, cron will fail if you only try to run one thing once a day. Putting in a dummy program to run every hour cures the problem. The.is never seems to come up since people generally do run something via cron on an hourly basis. This is clearly another inanity on the part of SCO for not having recompiled their utility.ies under the 386 compiler. Of course without bugs in the system, what would we have to talk about? -- aryeh@eddie.mit.edu mit-eddie!lees-rif!aryeh
debra@alice.UUCP (Paul De Bra) (02/05/89)
In article <455@berner.UUCP> richard@berner.UUCP (Richard Greenall) writes: >In article <13073@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes: >> [ doubtful explanation of cron problem deleted ] > >I don't think that that was the entire problem with cron. I also >run uucp a couple times an hour and still get the cron lockup >quite regularly with 2.3.1 I even added the /bin/true to run about >every half hour with little success. I even went back to the >cron in version 2.2.1 and installed that, and STILL got the >same symptoms. The cron problem exists in other versions of Unix as well. The time between events is irrelevant since cron is supposed to wake up every minute to check whether the crontab (or crontabs in newer releases) has changed. The only instances of cron falling asleep that I have seen occured in a system where cron had been swapped out. Apparently there is a bug in some Unix systems (not just Xenix and not only on intel processors!) that causes processes that are swapped out while sleeping to remain asleep for ever. (I mean waiting for the end of sleep(), not waiting for some other event like I/O). I never noticed the problem in my Xenix box because it has enough memory to avoid all swapping. Paul. -- ------------------------------------------------------ |debra@research.att.com | uunet!research!debra | ------------------------------------------------------
tif@cpe.UUCP (02/08/89)
Written 6:47 pm Feb 4, 1989 by alice.UUCP!debra in cpe:comp.unix.xenix >The cron problem exists in other versions of Unix as well. The time between >events is irrelevant since cron is supposed to wake up every minute to check >whether the crontab (or crontabs in newer releases) has changed. I thought this was pre-System V behavior. Paul Chamberlain Computer Product Engineering, Tandy Corp. {killer | texbell}!cpe!tif